Acid-modified copolymers of drying oil acids, maleic-polyhydric alcohol esters, and process of making same



Patented July 3, 1951 UNITED STATES PATENT OFFICE,

ACID-MODIFIED COPOLYMERS OF DRYING OIL ACIDS, MALEIC-POLYHYDRIC ALCO-IsignIiEESTERS, AND PROCESS OF MAKING Frank B. Root, Montclair, N. J.,assignor to Ellis- Foster Company, a corporation of New Jersey NoDrawing. Application September 17,1948, Serial No. 49,864

22 Claims.

fied composition wherein a monohydroxyl-containing drying oilacid-polyhydric alcohol ester is esterified both with a, polymerresulting from the conjoint polymerization of a liquid polymerizablemonomer with the maleic acid half-ester of said monohydroxy ester andwith another esterifiable acid.

It is an object of this invention to provide a process whereby solublecopolymers can be obtained from a wide range of proportions ofpolymerizable C=CH2 compounds. It is also an object to produce solublecopolymerized drying oil esters having improved drying characteristicsand capable of forming coating composition hav= ing great hardness, highdurability, and good water-resistance. Other objects will be apparentfrom the detailed description which follows.

In my copending application Serial No. 775,- 952, filed September 24,1947, of which the present case is a continuation in part, there isdisclosed a procedure which comprises essentially the steps of (1)formin a monohydroxy ester of general formula D1. 1POH, wherein D is theradical of a drying oil acid free from conjugated carbon-carbonunsaturation, P is the hydroxylfree residue of a polyhydric alcoholP(OH) n, and n is the number of hydroxyl groups in said polyhydricalcohol, (2) reacting 2 moles of this hydroxy compound with 1 mole of anunsaturated alpha-beta-dicarboxylic acid under such conditions that onlya half-ester is formed, whereby the reaction mixture consists of anequimolecular mixture of the monohydroxy compound Dn1POH and itsunsaturated dicarboxylic acid half-ester, (3) adding the copolymerizablecompound containing a single ethylenic linkage and heating the mixtureunder polymerizing but non-esterifying conditions to get the copolymerof the dicarboxylic acid half-ester, and finally (4) heating the mixtureunder e'sterifying conditions to esterify the carboxylic groups of thecopolymer with the monohydroxy ester.

(1) In forming the monohydroxyl-containing compound, the reactioninvolvesn-l moles of drying oil acids and 1 mole ,of-polyhydric alcohol.As in all reactions in which a polyfunctional compound enters, a mixtureof esters is possible and it is of utmost importance that the reactionproduct consists essentially of monohydroxy esters. Esters containingmore than one hydroxyl group must be at a minimum or noninfiuentialamount, otherwise gelation will occur in the final esterification stepbefore the acid number is adequately lowered. Also, polyhydroxycompounds may form half-ester with the unsaturated dicarboxylicanhydride in the second step, which contain more than one unsatu rateddicarboxylic acid group, and lead to premature gelation inv thepolymerization step. The reaction product from this step must be freefrom an influential amount of esters containing more than one hydroxylgroup.

In general, the reaction of n-l moles of dryin oil acids with 1 mole ofpolyhydric alcohol at a temperature between and 250 C. produces asatisfactory hydroxyl-containing ester product although, for certainpurposes, particularly with a polyhydric alcohol which contains arelatively large number of hydroxyl groups such as pentaerythritol orpolypentaerythritol, a slight excess (about 0.1 mole) of monocarboxylicacid may be used to advantage. This reduces the probability of freepolyhydric alcohol and esters containing more than one hydroxyl group.Also} the reaction temperature must not be high enough to produce anysubstantial polymerization of the drying oil ester, since theintermolecular polymerization product contains more than one hydroxylgroup and tends to cause gelation in the final step. A temperature belowabout 250 C. is suitable for makin the hydroxyl ester.

In place of drying oil acids, the drying oils themselves may bealcoholized with glycerol or other polyhydric alcohol to form amonohydroxy ester. The drying oils and the acids therefrom areunpolymerized and include those containing substantially no conjugatedunsaturation such as linseed, soya bean, sunflower seed, walnut,perilla, etc. Suitable esterifiable polyhydric alcohols are glycerol,polygylcerol, glycols and polyglycols (ethylene glycol, diethyleneglycol, etc), pentaerythritol, polypentaerythritol, trimethylol propane,etc. e

(2) The monohydroxy drying oil fatty acids-' polyhydric alcohol ester isheated with an unsaturated dicarboxylic acid anhydride such as maleic,chloromaleic, itaconic or citraconic an-. hydride. The correspondingacids may be used,

if desired, since they break down readily into the anhydride. Thereaction proceeds rapidly even at temperatures below 200 C. Thus, thetime and temperature inthis step are inadequate to cause esterificationor any reaction. other than addition of the anhydride to the hydroxyester with formation of the dicarboxylic acid halfester. anhydride and 2moles of the monohydroxy ester are used the result is an esterflablemixture of equal moles of the monohydroxy ester and its dicarboxylicacid half-ester. N molecules containing more than one unsaturateddicarboxylic acid radical are possible except what might result inminute amount from traces of esters containing more than one hydroxylgroup unavoidably derived from the first step. While the ratio of acidanhydride to monohydroxy ester is preferably 1 mole to 2 moles, since anexcess of hydroxyl groups insures reaction of all the acid anhydride,more or less of the anhydride may be used, as is explained later. Also,where a slight excess of drying oil acids is used in the first step, theproportion of acid anhydride may be correspondingly diminished if afinal low acid number is essential.

The temperature for the second step is between about 140 and 200 C. andpreferably between 170 and 180 C., and half-ester formation occurs in ashort time (e. g., less than 30 minutes at 170 C.).

A modification of the second step consists in reacting maleic anhydridewith a mixture of the monohydroxyl-containing polyhydric alcohol esterand monohydric alcohol such as hydroabietyl alcohol or stearyl alcohol.

(3) The next step is copolymerization of the unsaturated dicarboxylicacid half-ester of the mixture with a liquid monomeric unsaturatedpolymerizable compound in which the unsaturation is due to a singleterminal ethylenic linkage C=CH2. The latter compound may be amonohydric alcohol ester of acrylic or methacrylic acid, acrylonitrile,a vinyl ester of a saturated monocarboxylic acid (e. g., vinyl acetate),styrene, and nuclear-substituted styrenes such as chlorostyrene andmethyl styrene, a monovinyl ether, or a monobasic acid ester of allyl ormethallyl alcohol. The most available compound Is styrene. Theproportion of such compound may be varied over a wide range. Forexample, the polymerization mixture may comprise 5% of polymerizableC=CH2 compound and 95% of the esteriilable ester mixture, and extend toabout 90% C=CH2 compound and of the esteriflable ester mixture.positions of varied oil-length are possible.

The temperature required for copolymerization is below 200 C. and ispreferably between about 120 and 170 0., depending upon the boilingpoint of the C=CH2 compound. The reaction may be carried out underpressure, if desired, and also in the presence of about 1% or less of apolymerization catalyst such as benzoyl peroxide, acetyl peroxide,laurylperoxide, di-tertiary butyl peroxide, tertiary butylhydroperoxide, etc.

After polymerization has proceeded until the viscosity no longerincreases or increases very slowly, the solution is heated to drive offany unpolymerized compounds, which may be thus recovered.

(4) Esteriflcation to form the final product is carried out at 200 C. orhigher, for example at between 200 C. and 300 C. Since the reaction atthis stage is theoretically between a monohydroxy compound and apolycarboxylic compound, the polyester is of the linear type and doesnot reach an infusible gel-stage through esteriflcation. However, if aninfluential amount of When 1 mole of unsaturated dicarboxylic Thus,coating comesters containing more than one hydroxyl group is present,the mixture would naturally form a gel before the acid number isadequately lowered. A gel is formed on long heating through the normalbodying reaction of drying oil acid polyesters and the esteriflcation iscarried out as long as is necessary to obtain a soluble final ester oflow acid number. The acid number is preferably below 20.

The esteriflcation mixture is heated as stated above, and the heatingmaybe at atmospheric or reduced pressure. If vacuum treatment is used itis advisable to add an anti-foam agent (e. g., a

silicone oil), since products of high viscosity tend to foam.Esteriflcation may also be accomplished by azeotropic distillation ofthe water in the presence of a high boiling liquid such as xylene. Insome cases the unreacted monomer (e. g., styrene) of step 3 may be usedas the water-entraining liquid."

If desired, the final esterification step may be carried out in thepresence of other substances such as oil-soluble resins, drying oils,mixtures of drying oils and resins, or waxes. Since copolymerizationresults in the substantial disappearance of the unsaturation of thedicarboxylic acid radicals, these other substances may include materialcontaining conjugated double bonds such as tung oil or rosin. Also, ifdesired, the esteriflcation step may be carried out by baking theproduct from step 3 in the form of an applied finish, with or withoutother additions as noted above, including pigments and driers.

In the second step the unsaturated dicarboxylic acid anhydride reactsonly to form a half-ester. No diene reaction with the drying oil acidradicals is possible since the time is too short and the temperature isbelow 200 C. -A1so, duringthe copolymerization step the temperature istoo low for a diene reaction, and the copolymerization reaction betweenunsaturated dicarboxylic acid groups and C=CH2 groups is suii'icientlyfaster than any possible reaction between drying oil acids groups andC=CH2 groups. Thus, the process avoids side-reactions which increase thereaction-functionality of the reactants, and results in a soluble finalproduct. As noted above, the final ester is not permanently soluble andfusible since polymerization of the drying oil radicals ultimatelycauses gelation. However, esteriflcation occurs before this change takesplace, particularly when the esterification occurs under vacuum or inthe presence of an inert gas such as carbon dioxide or nitrogen.

The present invention consists in replacing part of the unsaturateddicarboxylic acid, which is preferably maleic anhydride, by anotheresteriflable acid. Although boric acid is suitable, the modifying acidis in general a carboxylic acid, either monocarboxylic orpolycarboxylic, and substituted or unsubstituted. Thus, 2 moles of themonohydroxy ester Dn-1POH are heated with from 0.3 to 0.9 mole (insteadof 1 mole) of maleic anhydride to the half-ester stage and anothersecondary or modifying acid is subsequently added in amount equivalentto the difference between 1 mole of maleic anhydride and the amount (0.3to 0.9 mole) used to form the maleic half-ester mixture.

The stage in the process at which the other acid is added is dependentupon the nature of the acid. For example, if phthalic is the modifyingacid, it may be added (a) along with the maleic, (hi immediatelyfollowing the reaction of the maleic, or (c) following thepolymerization step and either saturated fatty acids (e.

before or after removal of unreacted polymerizable monomer. If rosin isthe modifying acid, it should not be added until after unsaturatedmaleic groups have been eliminated by copolymerization. If the acidsecondarily added is maleic or i'umaric, the stage should be afterremoval of unreacted polymerizable monomer. In general the secondaryaddition of acid is made prior to or during the final esterificationstep.

The operating conditions when secondarily added acids are used areessentially the same as in the prior process.

The particular esteriiying acid chosen for secondary addition ormodification of the product depends upon the properties it confers. Forexample, phthalic anhydride gives a final product whose films arefasterdrying and have better adhesion than when phthalic is absent. A smallamount of rosin reacted in accordance with the invention improvesclarity in certain cases. Tung oil acids improve drying somewhat. Maleicanhydride or fumaric acid (as the secondary acid) give products ofincreased viscosity. An advantage of the process is that products ofvarying properties can be obtained. Also, in many cases the substitutionof part of the maleic acid by another results in lower cost. However,the principal advantage of the present process lies in the fact. thatthere is less possibility in Step 2 (half-ester formation) of producingcompounds having more than one maleic group which favors gelationduringcopolymerization, since there is large excessof hydroxyl groups in thatstep in the present process. An excess of hydroxy compound during theformation of the half-ester and during polymerization restrictsundesirable sidereactions, and subsequent esterification of this excess:produces a clear homogeneous soluble composition. The formation of aclear final product. is unexpected since the mere addition of suchsubstances as drying oils and drying oil alkyd resins to a preformedunmodified alkyd styrene copolymer, such as obtained by the priorprocess, results in turbidity. The modified products of the presentinvention have improved compatibility with drying oils and resins.

Among the acids which are applicable in the present process as modifyingagents of the maleic copolymer compositions are phthalic, succinic,adipic, sebacic, azelaic, benzoic, citric, maleic, fumaric, citraconic,itaconic, aconitic, tetrahydrophthalic,endo-methylene-tetrahydrophthalic. g., acetic, palmitic, stearic, etc.)unsaturated fatty acids (e. g., oleic, linoleic, linolenic, eleostearicor the mixed acids of drying oils), rosin, hydrogenated rosin and sorbicacid and the inorganic acid boric acid. Anothertype. of modifying acidmaterial comprises drying oil adducts such as from linseed or tung oilwith maleic anhydride or rosin-maleic anhydride adducts. A plurality ofmodifying acids can be used.

The products include reaction products ranging from oils to relativelyhard resins depending upon'the amount of copolymerized liquid monomer.They are soluble in esters, ketones and hydrocarbons, those containingmore of the copolymerized liquid monomer being soluble in aromatichydrocarbons or mixtures of aromatic hydrocarhens and mineral spiritsandthose containing less of the copolymerized monomer being soluble inaliphatic hydrocarbons such as straight mineral spirits. The productsare adapted for coating compositions and other uses such as printinginks, linoleum, oil cloth, or binders.

.The inclusion of an antiskinning agent or stabilizer in the varnish orenamel is usually advisable. If the stabilizer is heat-stable it can beadvantageously added during the final esterification; otherwise it isadded to the coating solution. The amount is generally from 0.05% to0.5% of the resin, which amount is insuflicient to retard drying.Hydroquinone, ditertiary butyl hydroquinone, resorcinol and phenylnaphthyl amine are examples of known stabilizers. Another type which isvery efiective comprises ketoximes such as dimethyl ketoxime or methylethyl ketoxirne. Another means of increasing the storage stability ofthe solutions is to add varying amounts of a resin such aspolycoumarone, polyindene or the resin obtained by polymerizingbeta-pinene.

The following examples are given to illustrate the invention.

Example 1.Rosin-modified styrene copolymer of soya-maleic-glyceride.

In a flask equipped with stirrer, carbon dioxide inlet and thermometer,3000 grams (3.4 moles) of refined soya bean oil, 164 grams (1.7 mo1es)of glycerol and 1 gram of litharge were heated. to

as cold-molding 230 C. in 1.25 hours and held at 230-245 C.

tertiary butyl peroxide.

for 2 hours. To 308 grams (0.5 mole) of the diglyceride thus formedthere was added 18.4 grams (0.19 mole) of maleic anhydride and themixture was heated with agitation for 15 minutes at 170 C. Theproductwas mixed with 246 grams of styrene, and 4.3 grams of tertiarybutyl peroxide, and heated under reflux so that the temperature rosegradually from C. to 167 C. over a period of 2.5 hours. Then 42 grams(0.12 mole) of rosin was added and the mixture heated for 1 hour at290-300 C. under CO2 at atmospheric pressure and 1 hour at 290-300 C.under a pressure of 25 mm. mercury. The product at room temperature wasa clear, tough, amber resin having an'acid number of 11 and a convertedstyrene content of 39%. in mineral spirits.

A varnish was prepared from the resin by dissolving 5 parts of it in amixture of 4 parts of mineral spirits and 1 part of xylene by weight andadding naphthenate drier to give 0.16% Pb and 0.02% Co based on solids.A film of this varnish dried to a tack-free condition in 6 5 hours atroom temperature. The dried film was tough and was unusually resistantto aqueous alkali.

Example 2.Tung oil acids-modified chloro- The resin was soluble styrenecopolymer of soya-maleic-pentaerythritol ester.

A 500-ml. flash equipped with agitator and therof maleic anhydride and213 grams (0.24 mole) of the monohydroxy ester obtained by heating 1mole of pentaerythritol with 3 moles of soya bean oil acids for 1 hourat 200-220 and then for 4 hours at 220230 C. The mixture of theanhydride and ester was heated for 10 minutes at 155-170 C. and, aftercooling to 150 C., the resulting product was dissolved in 55 grams ofmixed oand p-chlorostyrene containing 0.9 gram of di- A reflux-tube wasattached, and polymerization was effected by heating for 1.5 hours at-185 C. The polymerizate was mixed with 33 grams (0.12 mole) of tung andheating was continued ior 7 hours at 200-245 C. The product, afterfiltration to remove a trace oi suspended matter, was freed of solventunder reduced pressure. It wa a clear, reddish-brown oil having aviscosity of approximately 2-3, and an acid number of 8.

A varnish was made by dissolving the oil in mixed solvent containing 2parts of mineral spirits and 1 part of xylene by weight (50%non-volatiles) and adding cobalt naphthenate to give 0.03% Co based onoil. A film of this varnish aged for 3 days was unusually resistant towater and aqueous alkali.

Example 3.-Phthalic-modifled styrene copolymer oi soya-maleic-glyceride.

In a reactor equipped with thermometer and agitator, 308 grams (0.5mole) oi soya oil acidsdiglyceride (prepared as in Example 1) was heatedwith 18.4 grams (0.19 mole) of maleic anhydride for 15 minutes at 170 C.To the product. cooled to 125 0., there was added a solution containing270 grams of styrene and 1.8 grams of ditertiary butyl peroxide. tachedto the reactor and the solution was brought to a temperature of 150 C.and held at 150-163 C. for 1 hour. No appreciable refluxing occurredduring polymerization. Phthalic anhydride in the amount of 9.3 grams(0.06 mole) was added to the polymerizate and heating was continued for1 hour at 155165 C. The reflux tube was then replaced by a down-turnedcondenser and receiver and the batch was heated to 240 C. and held for1.25 hours, while a slow stream of carbon dioxide was passed through.During the course of this treatment a total of 29 grams of distillatewas evolved, includin a non-aqueous layer of 25 grams. The product was aslightly hazy,tough, amber-colored resin having an acid number of 19 anda converted styrene content of 43%.

A varnish was made from the product by reducing it to 50% solids withmixed solvent containing 4 parts of mineral spirits and 1 part ofxylene, and adding mixed naphthenate drier sutficient to give 0.06% Pband 0.02% Co based on solids. The varnish was clear after removal ofslight haze by filtration with 1% of a siliceous filter-aid. A film ofthis varnish dried dust-free in 0.5 hour and tack-free in 4 hours. Theovernight-dried film had a Sward hardness of 26. A film aged 3 days andimmersed for 3 days in tap water at 25 C. developed a barely perceptiblehaze which disappeared after exposure of the film in air for 0.5 hour.

Example 4.-Phthalic-modified styrene copolymer of soya-maleic-ethyleneglycol ester.

A reactor, equipped with thermometer, agitator, and steam-jacketedreflux condenser, was charged with 800 grams (3 moles) of soya bean oilacids and 186 grams (3 moles) of ethylene glycol. The mixture was heatedfor 5 hours at 180- 223 C., giving a mono-hydroxy ester of acid number5. A mixture of 124 grams (0.4 mole) of this ester and 9.8 grams (0.1mole) of maleic anhydride was heated for minutes at 160-170 C. Theacid-ester thus formed was mixed with 134 grams of styrene, 0.8 gram ofdi-tertiary butyl peroxide and 14.8 grams (0.1 mole) of phthalicanhydride, and heated under reflux for 3 hours at 150-180 C. Thereafterthe reflux condenser was arranged for distillation and the temperatureraised to 255 C. in 45 minutes and held at 255-268 C. for 1.25 hours,thus removing unreacted monomer and eflecting esteriflcation. Theproduct was a clear, amber, tacky resin having an acid number of 17 anda converted styrene con- A reflux tube was attent or 48%. An air-driedvarnish film obtained from this product was somewhat frosted.

Example 5.Sebacic acid-modified chlorostyrene copolymer ofsoya-maleic-glyceride.

A mixture of 123 grams (0.2 mole) oi soya oil acids-diglyceride(prepared as in Example 1) and 5 grams (0.05 mole) oi maleic anhydridewas heated under agitation for 10 minutes at 165-172" C. The acid-esterthus iormed was cooled to 142 C., and to it there was added 128 grams ofa monomer mixture consisting of orthoand para-chlorostyrene and 0.77grams of di-tertiary butyl peroxide. The resulting solution was heatedunder a reflux condenserior 10 minutes at -174 C. and then for 2.5 hoursat 174-183 C. The condenser was then turned for distillation and acarbon dioxide inlet was provided. Bebacic acid in the amount of 10grams (0.05 mole) was added and the temperature or the batch was raisedto 247 C. At this stage a cold pill or the product was opaque. Thetemperature was then raised to 300 C. over a period or 1 hour and afterthe flow of carbon dioxide was stopped, heating was continued for 0.5hour at 290-300 C. under a pressure of 35 mm. mercury. The resultingproduct had an acid number of 5.5 and a converted monomer content of47%. At room temperature it was a slightly tacky, rather tough,amber-colored, slightly turbid resin. A 50% solution of the product in amixture of 2 parts of mineral spirits and 1 part of xylene (by weight)was clear after filtration. Cobalt naphthenate was added to give 0.03%Co based on solids. A film of this varnish dried in 4 hours. After 5.5hours the film had a Sward hardness of 29.

Example 6.-Phthalic-modified styrene copolymer of linseed-maleicglyceride.

Linseed glyceride was made by heating 1760 grams (2 moles) of refinedlinseed oil, 92 grams (1 mole) of glycerol and 0.5 gram litharge at 240C. for 2 hours. In a reactor equipped with stirrer, thermometer andreflux condenser, grams of the diglyceride (0.25 mole) and 6 grams (0.06mole) of maleic anhydride were hsated for 10 minutes at C. Then 150grams of styrene and 3 grams of benzoyl peroxide were added andpolymerization was carried out by heating the mixture for 3 hours at150-160 C., after which the condenser was turned for distillation andthe temperature gradually raised to 240 C. During this period 33 gramsof unreacted styrene distilled. Nine grams (0.06 mole) of phthalicanhydride was added and the mixture was heated for 1.5 hours at 240-250C. in an atmosphere of carbon dioxide. The product was alight-colored,'soft, somewhat turbid resin of acid number 12.5.

A varnish was made by dissolving the product in a mixture of 2 partsmineral spirits and 1 part xylene to form a 50% solution and addingnaphthenate drier to give 0.16% Pb and 0.02% Co (based on solids). Thevarnish was clear after filtration and a film dried dust-free in 0.75hour and tack-tree in 2 hours.

Turbidity of such a resin may be overcome by adding a small amount ofglycerol along with the phthalic anhydride. However, this procedurecauses som'ewhat slower drying of the varnish.

Example 7.Sebacic-modifled styrene copolymer oflinseed-maleic-glyceride.

A mixture of 150 grams (0.25 mole) oi'linseed digiyceride prepared as inExample 6 and 6 grams of maleic anhydride (0.06 mole) was heated at 170C. for 5 minutes, after which 150 grams of produced a clear,light-colored, soft resin having a polymerized styrene content of 45%and acid number of 9.6.

A varnish prepared as in Example 6 dried dustfree in 0.5 hourandtack-free in 2 hours.

Example 8.Linseed maleic adduct-modified styrene copolymer oflinseed-maleic-glyceride.

A mixture of 150 grams (0.25 mole) of linseed oil acidsdiglyceride(prepared as in Example 6) and 9.2 grams (0.09 mol.) of maleic anhydridewas reacted for 20 minutes at 150-165 C. The acid-ester thus obtainedwas mixed with 109 grams of styrene and 0.8 gram of di-tertiary butylperoxide, and heated under reflux for 2.5 hours at 155-183 C. to eiiectpolymerization. The condenser was then turned for distillation. To thepolymerizate there was added 42 grams of an adduct (of acid number 83)obtained by heating linseed oil with 10% of maleic anhydride. the amountof adduct being equivalent to 0.03 mole maleic anhydride. The mixture ofmaleated oil and polymerizate was heated to %3 C. and held at thattemperature for 1.75 hours under carbon dioxide. The product at 25 C.was a semi-solid, tacky resin having an acid number of 17.5 and aconverted styrene content of 33%. It was compatible with raw linseedoil, tung oil, ester gum and cumarone-indene resin.

A varnish was prepared by dissolving the product in an equal weight ofmineral spirits and adding suflicient cobalt naphthenate to give 0.03%Co based on non volatiles. A film of this varnish exposed at roomtemperature was dust-free in 1 hour and tack-free in 3 hours. A filmaged 3 days had a Sward hardness of 20 and when immersed in tap waterfor 3 days it became only faintly turbid.

Example 9.-Boric acid-modified styrene copolymer oflinseed-maleic-glyceride.

A reactor equipped with stirrer and thermometer was charged with 150grams (0.25 mole) of linseed oil acids-diglyceride (prepared as inExample 6) and 9.2 grams (0.09 mole) of maleic anhydride and heated for20 minutes at 150- 165 C. The product was dissolved in 109 grams ofstyrene (to which had been added 0.8 gram of di-tertiary butyl peroxide)and the resulting solution was heated for 2.5 hours under reflux at155-183 C. to effect polymerization. After changing the condenser fordistillation and providing a tube for introducing carbon dioxide intothe batch, boric acid in the amount of 1.2 grams (0.02 mole) was addedto the polymerizate. Removal of unreacted monomer and esterificationwere eflfected by heating the mixed ingredients to 235 C. in 10 minutesand holding at that temperature for 1 hour. The resulting product,cooled to 25 C., was a pale, amber-colored, semisolid resin having anacid number of 17 and a converted styrene content of 37%.

A varnish prepared from this product had good drying characteristics.

Example 10.Rosin-phthalic-modifled styrene copolymer oflinseed-maleic-glyceride.

A reactor equipped with thermometer and stirrer was charged with 246grams (0.4 mole) of 10 linseed diglyceride (prepared as in Example 6)and 9.8 grams (0.1 mole) of maleic anhydride. The mixture was heated for10 minutes at C., and cooled to 150 C. To the acid-ester mixture thusformed there was added a solution consisting of grams of styrene and 1.4grams of di-tertiary butyl peroxide. To effect polymerization, themixture of ingredients was heated under reflux for 0.5 hour at 110167 C.and then for 1.5 hours at 167-170 C. At this point 11.2 grams (0.075mole) of phthalic anhydride and 16.6 grams (0.050 mole) of rosin wereadded. Provision was made for bubbling carbon dioxide 'through themixture and the reflux attachment was replaced by a distillation tubecontainin a 20 cm. vertical section. The reactants were heated accordingto the followingschedule:

0.3 hr. at 170-212" C. 3.0 hr. at 212-222" C. 0.5 hr. at 222260 C. 1.3hr. at 260 C.

Throughout this treatment the little remaining styrene monomer slowlydisappeared from the reaction chamber, partly by distillation and partlyby polymerization. In this manner the water of esterification waslargely removed by azeotropic distillation. The product thus obtained,when cooled to room temperature, was an amber-colored, tacky, semi-solidresin having an acid number of 10.7 and a converted styrene content of39% A varnish was prepared by dissolving a portion of the resin in anequal weight of mixed solvents (2 parts of mineral spirits plus 1 partof xylene by weight) and adding cobalt naphthenate to give 0.03% Cobased on non-volatiles. The varnish had a Gardner viscosity of A-B. Whena thin film of the varnish was cast on a glass panel and exposed at roomtemperature, it became dust-free in 0.75 hour and tack-free in 3 hours.Sward rocker hardness made after 4.5 hours and 24 hours exposure of thefilm were 22 and 34, respectively. The 24 hour aged film was clear,tough and unusually adherent.

Example 11.-Maleic acid-modified butyl methacrylate copolymer ofsoya-maleic-glyceride.

A mixture of 123 grams (0.2 mole) of soya oil acids-diglyceride(prepared as in Example 1) and 4.9 grams (0.05 mole) of maleic anhydridewas heated for 10 minutes at 160-170 C. The product of this reaction wasdissolved in 128 grams of butyl methacrylate to which had been added0.77 gram of di-tertiary butyl peroxide. The solution was heated underreflux as follows:

% hr. at 100-174 C. 6 hrs. at 174-193 C.

Unconverted monomer was removed under vacuum generated by awater-aspirator. Maleic anhydride in the amount of 4.9 grams (0.05 mole)was then added to the polymerizate, and the mixture was heated undercarbon dioxide at atmospheric pressure for 1.3 hours at 235 to 275 C.The flow of carbon dioxide was discontinued, vacuum was re-applied, andreaction was continued for 50 minutes at 275 C. The product obtained wasa clear, amber, viscous oil having an acid number of 7.2 and a convertedmonomer content of 42%. It was compatible with raw or bodied linseedoil.

It will be understood that it is intended to cover all changes andmodifications of the examples of the invention herein chosen for thepurpose of illustration which do not constitute 11 departures from thespirit and scope of the invention.

I claim:

1. The process of making coating material. which comprises the steps of:(l) heating 2 moles of a monohydroxyl-containing ester of formulaDn-lPOH, wherein D is the acid radical of an unpolymerized drying oilacid free from conjugated unsaturation, P is the hydroxyl-free radicalof an esterifiable polyhydric alcohol P(OH)n, and n is the number ofhydroxyl groups in said polyhydric alcohol, with from 0.3 to 0.9

.mole of maleic anhydride at from 140 C. to 200 C. to form a maleic acidhalf-ester in the presence of an excess of said hydroxy-ester, (2)adding a liquid monomeric unsaturated polymerizable compound in whichthe unsaturation is due to a single terminal ethylenic group C=CHz andwhich is copolymerizable with said maleic half-ester and heating themixture at between 120 C. and below 200 C. to copolymerize same, theproportion of liquid monomeric compound in the mixture being from to90%, and (3) adding a carboxylic acid reactable only by esterificationin amount equivalent to the difierence between 1 mole of maleicanhydride and the amount thereof used in step 1, and heating thecomposition at from 200 to 300 C. to esterify same.

2. The process of making coating material, which comprises the steps of:(1) heating 2 moles 01. a monohydroxyl-containing ester of formulaDn-IPOH, wherein D is the acid radical of an unpolymerized drying oilacid free from conjugated unsaturation, P is the hydroxyl-free radicalof an esterifiable polyhydric alcohol P(OH)n, and n is the number ofhydroxyl groups in said polyhydric alcohol, with from 0.3 to 0.9 mole ofmaleic anhydride at from 140 C. to 200 C. to form a maleic acidhalf-ester in the presence of an excess of said hydroxy-ester, (2)adding styrene and heating the mixture at between 120 C. and below 200C. to copolymerize same, the proportionof styrene in the mixture beingfrom 5% to 90%, and (3) adding a carboxylic acid reactable only byesterification in amount equivalent to the difierence between 1 mole ofmaleic anhydride and the amount thereof used in step 1, and heating thecomposition at from 200 to 300 C. to esterify same.

3. The process of claim 2, wherein D represents the radical of linseedoil acids.

4. The process of claim 2, wherein D represents the radical of soya beanoil acids.

5. The process of making coating material. which comprises the stepsof 1) heating 2 moles of the diglyceride of soya bean oil acids at from140 to 200 C. with from 0.3 to 0.9 mole of maleic anhydride to form amaleic acid half-ester of soya acids-diglyceride in the presence of anexcess of said diglyceride, (2) adding styrene and heating the mixtureat between 120 C. and below 200 C. to copolymerize same, the proportionof styrene in the mixture being from 5% to 90%, and (3) adding rosin inamount equivalent to the difference between 1 mole of maleic anhydrideand the amount thereof used in step 1, and heating the composition atfrom 200 to 300 C. to esterify same.

6. The process of making coating material, which comprises the steps of:(1) heating 2 moles of the diglyceride of soya bean oil acids at from140 C. to 200 C. with from 0.3 to 0.9 mole of maleic anhydride to form amaleic acid halfester of soya acids-diglyceride in the presence of anexcess of said diglyceride, (2) adding styrene and heating the mixtureat between 120 C. and below 200 C. to copolymerize same, the proportionof styrene in the mixture being from 5% to and (3) adding phthalicanhydride in amount equivalent to the difference between 1 mole ofmaleic anhydride and the amount thereof used in step 1, and heating thecomposition at from 200 to 300 C. to esterify same.

'1. The process of making coating material, which comprises the steps of(1) heating 2 moles of the diglyceride of linseed oil acids at from 140C. to 200 C. with from 0.3 to 0.9 mole of maleic anhydride to form amaleic acid halfester of linseed acids-diglyceride in the presence of anexcess of said diglyceride, (2) adding styrene and heating the mixtureat between C. and below 200 C. to copolymerize same, the proportion ofstyrene in the mixture being from 5% to 90%, and (3) adding sebacic acidin amount equivalent to the difierence between 1 mole of maleicanhydride and the amount thereof used in step 1, and heating thecomposition at from 200 to 300 C. to esterify same.

8. The process of making a composition suitable for coating purposes,which comprises the steps of: (1) heating 2 moles of the diglyceride ofsoya bean oil acids at from C. to 200 C. with 0.75 mole of maleicanhydride to form a half-ester of soya acids-diglyceride from all themaleic anhydride, (2) adding styrene and heating the mixture at between120 C. and below 200 C. to copolymerize same, the proportion of styrenein the mixture being from 5% to 90%, and (3) adding 0.5 mole of rosinand heating the composition at from 200 C. to 300 C. to esterify same.

9. The process of making a composition suitable for coating purposes,which comprises the steps of: (1) heating 2 moles of the diglyceride ofsoya bean oil acids at from 140 C. to 200 C. with 0.75 mole of maleicanhydride to form a halt-ester of soya acids-diglyceride from all themaleic anhydride, (2) adding styrene and heating the mixture at between120 C. and below 200 C. to copolymerize same, the proportion of styrenein the mixture being from 5% to 90%, and (3) adding 0.25 mole ofphthalic anhydride and heating the composition at from 200 C. to 300 C.to esterify same.

10. The process of making a composition suitable for coating purposes,which comprises the steps of: (1) heating 2 moles of the diglyceride oflinseed oil acids at from 140 C. to 200 C. with 0.5 mole of maleicanhydride to form a half-ester of linseed acids-diglyceride from all themaleic anhydride, (2) adding styrene and heating the mixture at between120 C. and below 200 C. to copolymerize same, the proportion of styrenein the mixture being from 5% to 90%, and (3) adding 0.5 mole of sabacicacid and heating the composition at from 200 C. to 300 C. to esterifysame.

11. A varnish comprising the product of claim 13 dissolved in a volatilehydrocarbon solvent therefor.

12. A varnish comprising the product of claim 14 dissolved in a volatilehydrocarbon solvent therefor.

13. Coating material comprising an ester consisting of amonohydroxyl-containing polyhydric alcohol-drying oil acids ester havingthe formula Dn-lPOH, wherein D is the acid radical of drying oil acidsfree from conjugated unsaturation, P is the hydroxyl-free radical of anesteriflable 'polyhydric alcohol P(OH)1|. and n is the number theunsaturation is due to a single terminal ethylenic linkage C=CH2 andwhich is copolymerizable with said maleic acid half-ester, theproportion of monomeric compound in the mixture being from 5% to 90%,and (B) a carboxylic acid reactable only by esterification, the maleichalf-ester being equivalent to from 0.3 to 0.9 mole of maleic anhydrideand said esterifiable carboxylic acid being equivalent to the differencebetween 1 mole of maleic anhydride and th amount forming the half-ester,as produced by the process of claim 1.

14. Coating material comprising an ester consisting of amonohydroxyl-containing polyhydric alcohol-drying oil acids ester havingthe formula Dn-1POH, wherein D is the acid radical of drying oil acidsfree from conjugated unsaturation, P is the hydroxyl-free radical of anesterifiable polyhydric alcohol P(OH)11 and n is the number of hydroxylgroups in said polyhydric alcohol, esterified with: (A) the polymerresulting from the conjoint polymerization of a mixture of (a) a maleicacid half-ester of said monohydroxylcontaining ester and (b) styrene inamount equal to 5% to 90% of the mixture, and (B) a carboxylic acidreactable only by esterification. the maleic half-ester being equivalentto from 0.3 to

0.9 mole of maleic anhydride and said esteriflable carboxylic acid beingequivalent to the difference between 1 mole of maleic anhydride and theamount forming the half-ester, as produced by the process of claim 2.15. The product of claim 14 in which D represents the radical of linseedoil acids.

16. The product of claim 14 in whi D represents the radical of soya beanoil ac ds.

17. The product as produced by the method of claim 5.

18. The product as produced by the method of claim 6.

19.' The product as produced by the method of claim 7.

20. The product as produced by the method of claim 8.

21. The product as produced by the method of The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,190,789 Hubbuch Feb. 20, 19402,308,495 D'Alelio Jan. 19, 1948 2,392,710 Wakeford et al Jan. 8, 19462,457,657 Glick Dec. 28, 1948

1. THE PROCESS OF MAKING COATING MATERIAL, WHICH COMPRISES THE STEPS OF:(1) HEATING 2 MOLES OF A MONOHYDROXYL-CONTAINING ESTER OF FORMULADN-1POH, WHEREIN D IS THE ACID FREE FROM CONUNPOLYMERIZED DRYING OILACID FREE FROM CONJUGATED UNSATURATION, P IS THE HYDROXYL-FREE RADICALOF AN ESTERIFIABLE POLYHYDRIC ALCOHOL P(OH)N, AND N IS THE NUMBER OFHYDROXYL GROUPS IN SAID POLYHYDRIC ALCOHOL, WITH FROM 0.3 TO 0.9 MOLE OFMALEIC ANHYDRIDE AT FROM 140* C. TO 200* C. TO FORM A MALEIC ACIDHALF-ESTER IN THE PRESENCE OF AN EXCESS OF SAID HYDROXY-ESTER, (2)ADDING A LIQUID MONOMERIC UNSATURATED POLYMERIZABLE COMPOUND IN WHICHTHE UNSATURATION IS DUE TO A SINGLE TERMINAL ETHYLENIC GROUP >C=CH2 ANDWHICH IS COPOLYMERIZABLE WITH SAID MALEIC HALF-ESTER AND HEATING THEMIXTURE AT BETWEEN 120* C. AND BELOW 200* C. TO COPOLYMERIZE SAME, THEPROPORTION OF LIQUID MONOMERIC COMPOUND IN THE MIXTURE BEING FROM 5% TO90%, AND (3) ADDING A CARBOXYLIC ACID REACTABLE ONLY BY ESTERIFICATIONIN AMOUNT EQUIVALENT TO THE DIFFERENCE BETWEEN 1 MOLE OF MALEICANHYDRIDE AND THE AMOUNT THEREOF USED IN STEP 1, AND HEATING THECOMPOSITION AT FROM 200* TO 300* C. TO ESTERIFY SAME.